Atmosphere heat-treating furnace



v2 SheetsjSheef A. KRAUSCOPE ET AL Filed June 7, 1941 ATMOSPHERE HEATTREATING F-URNACE July 18, 1944.

July 18, 1944. AQKRAUSCOPE T-:T AL

ATMOSPHERE HEAT TREATING FURNACE 2 sheets-sheet 2 Filed June '7, 1941WITNESSES:

ATTORNEY Patented July 18, 1944v r UNITED STAT ATMOSPHEREHET-TREATINGFURNACE.

Albert Krauscope, Jeannette, and 4Gerhard P. s Lessmann, Forest Hills,Pa.,`assignors to Westinghouse Electric & Manufacturing Company,4 EastPittsburgh, Pa., a corporation 'of Pennsyl- Vania Application June19411seria`1 No. 396,996

3 claims. (o1.- ,2o-'68) Our invention relates generally toheat-treating furnaces of a type having a heating-chamber in which acharge is heat-treated while surrounded by a desired atmosphere, andmore particular-1y relates to a heat-treating furnace having abottomcharging-opening closed by a suitable bottom closure or door, andprovided with a gassealing means for limiting leakage of atmosphereorair around the edges of the closure in the closing position thereof. yf

It is an object of ourinvention to provide .a .heat-treating furnacehavinga bottom charging.- opening, through which a charge is eitherraised or lowered, or both, the charging-opening being provided with aclosure means provided with a gas-sealing member-means adapted tocontact the wall-structure of the v heating-chamber to provide agas-sealing between the closure and the wall-structure.

' It is an object of our invention to provide a gas-sealing means for afurnace of the type described, which sealing means is automaticallyoperable to effect its sealing function when the closure seats` in thecharging-opening of the furnace.

It is a further object of our invention to provide a gas-sealing meansfor a furnace of the type described, in which the wall-structure of thefurnace is provided with a gas-sealing contact .member-means engageableby a gas-sealing closure member-means on the closure when the closure ismoved to closing position, the closure member-means being disengageablefrom the gassealing contact member-means when the closure ismoved fromclosing position.

In accordance with our invention, the closure is provided with aU-shaped trough-member near its edges; A structure, includingcompressible material, is slidable in this trough-member, andv pressedupwardly therein by spaced compression springs, with the movement of thestructure howengages the co-operating gas-sealing contact thosementioned above, will be apparent from the following descriptionthereof. which is to be taken in connection with the accompanyingdrawings, on varying scales, in which: s

Figure 1 is a transverse sectional view showing,somewhat.diagrammatically, a furnace embodying our invention, 1 1

Fig. 2 is a vertical sectional view through the spring-pressed structureof thel closure member- `means of the gas-sealing means, f Fig-3 is afragmentary elevational vView of the closure member-means of thegas-sealing means, which is at one corner of the closure,

Fig.` 4 is a fragmentary plan View of the closure member-means of thegas-sealing means,

Fig'. 5 is an elevational view of a, Vcontact element.v of the closuremember-means of the'gassealing means, which contact element is ametallic sheet. It is yshown as it appears in one stage of itsmanufacture,

Fig. 6v is an elevational view of a barused as part of the closureymember-means of the gas- `sealing means, y

Fig. 7 is a cross-sectional view of a modified form of closuremember-means for a gas-sealing means in accordance with ourinvention,and

Fig; 8 is a, plan view, similar to Fig. 5, of a contact element of themodified' closure member-means.

Referring more particularly toFig. 1, a heat- 'treating furnace isshown, comprising a wallstructure I comprising four vertical walls 2covered by a top wall 4, the vertical walls vand top wall defining aheating-chamber 6 adapted to heat-treat a .charge while enveloped by anysuitable controlled or other desired atmosphere. The wall-structure I issuitably encased in an outer metallic shell 8.v l v The furnace may beconstructed in the manner shown and claimed in the copending applicationof ElmerK. Hansen, Serial No. 397,007, filed concurrently herewith, andassigned to th assignee of this application.'

The furnace I is provided with a bottom charging-opening Il) throughwhich a charge is adapt,- ed to be raised or lowered, or both, the,charge being adapted to rest on a closure indicated in its entirety bythe reference numeral I2.

A closure of the type shown in more particular: ly described and claimedin the application of G. P. Lessmann, Serial No. 396,997, filedconcurrently herewith and assigned to the assignee of this application.The closure I2, briefly, comprises a gas-impervious bottom or base plateI4 Asupporting a refractory hearth I 6 which is shaped to conform to thecharging-openings I8, but is slightly smaller. A gas-sealing means,indicated in its entirety by the reference numeral I8, is provided nearthe edges of the base plate I4 and is around the hearth I6.

The closure I2further comprises asuitable understructurefor ,rotatablysupporting anpair of spaced front wheels and spaced rear wheels 22,

the front wheels riding on a pair of rails such as pistons and pistonrods pivotally connected to the clevises at the corners of the closure.The

cylinders are also pivotally supported, as at 32, lto

accommodate the'travelof the closure in its combined horizontal andAvertical movements.

"I'he rails 24 and 26V are provided with a `horizontal portion 34 uponwhich' theclosure I2 vrests in'uncovering position. The curvature of therails vis such that when Vthe closure is moved from its extreme openposition on the horizontal portion '34 of the rails 24 and 26, toclosing position, it rides upwardly with lgradually increasing verticaldirectional components soV that `the hearth I6 suitably seats in thecharging-opening I0, and so that the gas-sealing means I8 is madeeffective.

Inaccordance with our invention, the gas-sealing means vrI8 `comprises astationary contact member-means 36 at the bottom of the vertical walls2, the contact member-means being gastightly secured to the outer shell8. The contact 'member-means preferably is a frame-like plate whoseedges can be welded to, or made integral with, the shell 8, and which iscompletely around the wall-structure I. The gas-sealing means I8.further comprises a closure member-means 38 on the closure I2, capableof cooperating with the contact member-means 36 by contact or abuttingengagement.

The closure member-means 38 comprises a trough-member 38 around thehearth I6, followfing the edges Aof the base plate I4, this troughareinside the springs 44 and aligned with the i vshort tubes 46., A-plurality of bars r48 are arranged end-to-end in the trough-member 39,.

`The closure member-means 38 further comprises a plurality ofcontact-sheets 52, each of which is bent in the form of an vinverted U,each contact-sheet having a .top portion 54 and depending legs 56 andj58, .the legs being slidablein the V'trough-member 33 oi the closuremembermeans, the leg 58 sliding on the side of the leg '42 offthetrough, andthe leg 56 `sliding onthe side of the leg 40 of the trough.Compressible mate-'- rial 60, which preferably comprises a plurality ofsheets of a Compressible substance, such as asbestos gasketing,or otherheat-resistant and heatinsulating sheet-material, is placed between thetop portion 54 of the contact-sheets 52 and the bars 48, the bars beingnarrower than the U of the contact-sheets 52. v

The springs 44 are compression springs so that they normally tend toforce a bar 48, the compressible material 6I] thereon, and an associated5U -s'haped contact sheet 52 upwardly, this motion, however, beinglimited by providing a cut-out A.groove or hole `62 vvin'a leg, shown asthe leg 58 of .the U -shaped contact-sheet 52, in which hole or groove62 the stem of a screw 64 extends, the screw being threaded in anysuitable threaded hole in a leg 42 of the closure member-means 38,

Aa plurality of `grooves 62 and screws 64 being spaced along thegas-sealing means.

The closure member-means 38 of the gas-sealing means I8 follows theedges of the base plate 'I4 lan-d 'a vcorner of the arrangement is shownin Fig 4, in'which two right-angular U-shaped contact-sheets 52 abuteach other, and similar abut- 'ting joints are provided between theupstanding legs V4!! and between the uptsanding legs 42 of thetrough-'member '39 of the closure member-means Fig. 5 shows acontact-sheet 52, this sheet being provided with a plurality of spacedV-shaped cut-outs 'Ill along the legs 50, and I2 along the leg 56. Inassembling the contact-sheet, the legs 56 and 58 are bent over toprovide the proper top portion 54, whichis solid and flat. The V cutouts10 and 'I2 are provided to permit a certain ydegree of lengthwiseIlexibility in the U-shaped contact-sheet 52 and thereby assure a goodcontact 'between lthe contact member-means 36 of the wall-structure andthe top portion 54 of closure member-means.

In operation. and assuming the closure in open position, `the springs'44 move the U-shaped contact-sheet or -sheets '52 'upwardly as far asthe screws 64 permit, and When the closure isV moved to closingposition, the tops 54 will engage the vframe-like contact member-means'36. As the closure i'siorcibly moved into nal Aclosing position -by`the pneumatic cylinder 28, they springs 44 are .compressed and the legs40 and 42 of the trough-member 39 slide upwardly with respect to thevlegs 56 an-d 58 of the U-shaped contactsheets 52, therebyrcompressingthe compressible material '66 between the bars 48 and the top portions54 which no longer can move upwardly because of their engagement withthe frame-lil-re contact membermeans "36 of the wall-structure I,.Compression of the material 60 closes the .open portions of the cut-outsl0 and 12. The

stack o asbestos strips 60 constitutes a substantially gas-tightsealing-means which protrudes from the trough .39 andlengages the bottomseal- 'ing-edge 3E of the furnace. Excessive wear at thecontact-.surface of the` asbestos is prevented :by the metalsurface-lining 54 thereon. The llexib'ility of the asbestossheet-.material enables it .to close the .gaps which would yotherwise beformed by the inevitable warping of the door or `closure-member, due to`the excessive heat of the furnace., and Yat the same time the asbestosvitself is able to withstand' the heat and to provide heat-insulationfor' shielding the springs 44 from the furnace-heat. The metalcontact-strip 54 of the asbestos air-sealing means is itself keptiiexible by having its asbestos-engaging sideportions "56 'in ktheforrnof a plurality of discrete prongs 55, instead of using a continuoussheetmetal channel, which would be more rigid.

The springs M, back of the asbestos sealingstrips EQ, provide thenecessary elasticity of the sealing-surface. The pressure of the springsdi! further forces the top portions 52 of the U-shaped Contact sheets 52snugly against the contact member-means 36. When the closure is moved toopen position, the closure member-means 3B ulti- 'mately disengages theContact member-means 3S in an obvious manner. It is, of course, highlydesirable to move the closure upwardly to Closing position when the twomember-means of the gas-sealing means I8 engage. However, slighthorizontal movement is also tolerable because the top portions d of thevU-shaped contact-sheets 52 can slide on the frame-like plate contactmember-means 36.

Figs. '7 and 8 show a modied form of closure member-means which isadapted to cooperate u with a contact member-means on the bottom of theWall-structure l which is in the form of a depending narrow frame. Inthis figure a U- shaped trough-member 80 having small upper inturnedanges 82 is provided for receiving a plurality of compression springs 84which press against one or more bars 88. Above the bars 86 is placedcompressible material 88 which is topped by metallic contact-sheet or-sheets 90 having down-turned lugs 92, slidable on the sides of thetrough-member, and a top portion 94 which engages a frame-like contactmember-means 96 gas-tightly secured under the wall-structure I, to theouter shell 3. The anges 82 limit upward action of the springs 84.

In the operation of this modication, upward movement of the trough 80,when the closure I2 is seating in the charging-opening l0, will causeengagement of the top portion 94 of the closure member-means with thestationary contact member-means 95 depending from the wall-structure l.This contact engagement [between the top portion 94 and the 'contactmember-means 86 takes place, as in the prior modification, before theclosure is fully seated in the charging opening in proper closingposition. As the closure moves upwardly to full closing position, thecompressible material 88 is compressed snugly against the side walls ofthe trough 80.

While we have shown our invention in forms which We now believe to bepreferred embodiments thereof, it is obvious that many changes may ibe'made and equivalents substituted in the particular constructions shown.

We claim as our invention:

1. A sealing means adapted to bar the leal;- age of gas through thejoint between a furnacedoor and the door-seat of a furnace, comprising aheat-resistant elongated trough-member; a compressible and flexiblestack of heat-resistant and heat-insulating material restrictablymovable in said trough-member; means comprising a plurality of spacedspring-means between the bottom of said trough-member and said stack forpressing said stack outwardly at a plurality of points; and a exilblesheet-metal means comprising discrete side-prongs for engaging the sidesof said stack and of said trough-member and comprising a contact-portionon the outer side of said stack between the said sides thereof; saidstack being of such height as to extend lbeyond side-edges of saidtrough-member and to seal the spaces between said side-prongs in seaiingpositions of said sealing means.

2. A sealing means adapted to bar the leakage of gas through the jointbetween a furnace-door and the door-seat oi a furnace, comprising aheat-resistant elongated trough-member; a compressible and flexiblestack of heat-resistant and heat-insulating material restricta'blymovable in said trough-member; a iiexihle sheet-metal means havingdiscrete side prongs engaging the sides of said stack and slidablyengaging the sides of said trough-member, said sheet-metal means furthercomprising a contact-portion from which said side-prongs extend, saidcontact-portion bei ing on the outer side of said stack between the saidsides thereof; and means for exerting pressure on said stack along thelength of said troughmember for compressing said stack in sealingpositions of said sealing means; the height of said stack being such asto extend beyond the side-edges of said trough member and to seal thespaces between said slide-prongs in such sealing positions of saidsealing means.

3. The invention of claim l characterized :by said contact-portion ofsaid sheet-metal means comprising a substantially solid, flat andelongated metal-member, the side-prongs extending suiciently close tosaid elongated metal-member to permit lengthwise deformation thereof.

ALBERT KRAUSCOPE. GERHARD P. LESSMANN.

